The present invention relates generally to laser produced plasma extreme ultraviolet systems, methods and apparatus, and more particularly, to systems, methods and apparatus for droplet management in a laser produced plasma extreme ultraviolet system.
Laser produced plasma (LPP) extreme ultraviolet (EUV) systems produce a plasma by irradiating a droplet of a plasma target material with a source laser. The resulting plasma emits light and a desired wavelength, in this instance, EUV (e.g., less than about 50 nm wavelength and including light at a wavelength of about 13.5 nm or less).
Unfortunately irradiating the droplet of the plasma target material can result in debris from the droplet. The debris can be deposited on the collector mirror and other inner surfaces of the LPP system chamber. The deposited debris can also reduce the amount of EUV light output.
Further, some of the droplets of the target material are not irradiated by the source laser and as a result may produce splashes and other micro-particles and debris that can become deposited on the inner surfaces of the LPP chamber.
In view of the foregoing, there is a need for providing better control of the micro-particles and debris generated during the process of operating in an LPP EUV light source.